There is a constant and eager need for high-performance absorbents and/or fibrous materials.
It is known that foams are absorbent materials used in many industries in enormous volume, e.g. for recording and retention of liquids, for insulation of buildings or for packaging. The vast majority of these foams is produced in the synthesis of fossil raw materials and thus is not available sustainably. Examples include polystyrene and polyurethane.
What is more, the use of synthetic co-polymers of acrylic acid and sodium acrylate as an absorbent in hygienic products, particularly in diapers increasingly extended.
The swelling capacity of these known absorbents is of course a crucial criterion of their performances.
The absorbent materials with high water absorption capacity could have also important applications as plant substrates or to improve compost mixtures. In this perspective, said absorbent materials must be biodegradable, which is obviously not true for the above mentioned the synthetic foams.Fibrous materials are a category of absorbents different from the foams, and which could be too in crop applications.
In these respects, bio-sourced materials appear to be good candidates as raw materials for the production of absorbents and/or fibrous products, which could be used in applications where their absorption, water-swelling and fixation capacities are required. Plants may so provide a sustainable supply of foams and/or fibrous materials enabling applications in the planting area.
DE 42 22 139 A1 describes a filler made from stem pieces of plants with a high content of pith, e.g from corn stalks. These used plants are in the mature state. The manufacturing process consists in cutting the plants, in picking out the leaves, in bundling and in drying the stalks, by leaving them laid in the field, up to reach a dry content of 80-90% by weight. The dried stalks are then cut into 0.5-10 cm length cylinders for use as pore former for porous building materials, such aerated concrete, insulation boards and tiles, as packaging material or as carriers for odoriferous substances against vermin or for plants fertilizer.
EP0470596A2 describes an absorbent material made from corn stalks in granulated form (granulometry comprised between 10 and 150 mesh: (2 mm-100 μm). The manufacturing method comprises the husking, the denoding, the crushing and the separation by vibrating sieving, or alternatively, a wet processing with subsequent dewatering and drying. Said absorbent material derived from maize stem is used to make a disposable absorbent article (diaper, woman's hygienic pad, compress). Said manufacturing method is not industrial and does not make it possible to separate the different components of the maize stalk, namely the pith, the bark, the leaves. The 2 mm-100 μm granulates according to EP0470596A2 contain a mixture of pith, bark and leaves.
The invention aims at addressing at least one of the above problems and/or needs:                a) Providing a method for the production notably of superabsorbent pellets and/or of a fibrous material from crop residues, said method being swift and industrial;        b) Providing a method for the production notably of superabsorbent pellets and/or of a fibrous material from crop residues, said method making it possible to separate easily and efficiently pith, bark and leaves;        c) Providing a method for the production notably of superabsorbent pellets and/or of a fibrous material from crop residues, said method making it possible to get some superabsorbent pellets which water absorption capacity is greater than or equal to 5 times its own weight and which largest dimension (length) is greater than or equal to 2 mm;        d) Providing a method for the production notably of superabsorbent pellets and of a fibrous material from crop residues, said method making it possible to get at an industrial scale and simultaneously and distinctively superabsorbent pellets and a fibrous material with different exploitable functionalities;        e) Providing a method for the production notably of superabsorbent pellets and/or of a fibrous material from crop residues, said method making it possible to get some superabsorbent pellets which density in a non-compressed form—expressed in kg/m3 is comprised between 10-100;        f) Providing superabsorbent pellets and/or a fibrous material having the above mentioned specifications: manufacturing features, absorption features; density;        g) Providing superabsorbent pellets useful as absorbent/filter/elimination means of gaseous and/or liquids products originating from animal excrements, liquid hydrocarbons, including oil and its derivatives or as support for chemical treatment of any substrate, said support possibly including at least one active ingredient, useful as processing aid;        h) Providing a fibrous material as fertilizer, and/or peat substitute, and/or as crop aid, packaging material, paper pulp, insulation material, or components thereof.        